MOSFET Voltage Drop Detection Circuit Without Reference Amplifiers
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Solution Overview
Problem
Conventional circuits for detecting power supply voltage drop require a large circuit scale, consuming a significant amount of current due to the necessity of reference voltage circuits, voltage dividing circuits, and differential amplifier circuits.
Innovation Solution
A circuit design that eliminates the need for reference voltage, voltage dividing, and differential amplifier circuits by using a combination of NMOS and PMOS transistors with constant current circuits to detect power supply voltage drops, reducing circuit scale and current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reference voltage circuit, voltage dividing circuit, and differential amplifier circuit are used to detect power supply voltage drop, then detection accuracy is improved, but circuit scale increases and current consumption increases
Solution Approach 1:
The patent extracts and eliminates the reference voltage circuit, voltage dividing circuit, and differential amplifier circuit from the conventional voltage drop detection system. By removing these complex components and replacing them with a simplified transistor-based detection mechanism, the circuit scale is reduced while maintaining the essential detection function through direct voltage comparison at the transistor gate.
Solution Approach 2:
The detection circuit uses the power supply voltage itself to control the transistor operation without requiring external reference voltage circuits or voltage dividing circuits. The transistor naturally responds to voltage drops through its threshold voltage characteristics, eliminating the need for separate reference and division circuits, thereby reducing overall circuit complexity.
2Measurement precision
If conventional reference voltage circuit, voltage dividing circuit, and differential amplifier circuit are used to detect power supply voltage drop, then detection accuracy is improved, but current consumption increases
Solution Approach 1:
The patent removes the power-consuming reference voltage circuit, voltage dividing circuit, and differential amplifier circuit from the system. The simplified transistor-based detection requires minimal current to operate, as it relies on the inherent voltage-threshold characteristics of the transistor rather than active reference and amplification circuits, thereby significantly reducing current consumption.
Solution Approach 2:
The patent replaces complex, power-intensive circuits with a simple transistor-based detection mechanism that consumes minimal power. This simplified approach uses the transistor's natural switching characteristics at threshold voltage levels, eliminating the need for continuous power consumption by reference and amplification circuits.
3Reliability
If conventional reference voltage circuit, voltage dividing circuit, and differential amplifier circuit are used, then voltage drop detection capability is improved, but production complexity and costs increase
Solution Approach 1:
The patent extracts and removes multiple circuit modules (reference voltage circuit, voltage dividing circuit, differential amplifier circuit) that complicate the manufacturing process. By retaining only the essential transistor-based detection function, the number of fabrication steps, component interconnections, and quality control requirements are reduced, thereby lowering production complexity and costs.
Solution Approach 2:
The patent merges the functions of reference voltage generation, voltage division, and differential amplification into a single transistor-based detection mechanism. This consolidation eliminates the need for multiple separate circuit modules and their associated interconnections, simplifying the manufacturing process and reducing production costs while maintaining detection capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed circuit effectively detects power supply voltage drops with a smaller circuit scale, reducing current consumption and eliminating the need for trimming processes, thereby preventing semiconductor device malfunction and enhancing production efficiency and cost-effectiveness.
Implementation Method 1
a first transistor that is of a first conductive type and generates a source voltage based on a voltage obtained by subtracting an absolute value of a threshold voltage and an overdrive voltage from the power supply voltage
Implementation Method 2
a third transistor that is of a second conductive type and generates a source voltage based on a voltage obtained by adding an absolute value of a threshold voltage and an overdrive voltage to a ground voltage
Data Source
AI summary
Provided is a circuit for detecting power supply voltage drop having a small circuit scale. An NMOS transistor (12) generates a source voltage based on a voltage obtained by subtracting an absolute value of a threshold voltage and an overdrive voltage from a power supply voltage with reference to the power supply voltage. An NMOS transistor (17) is turned on/off based on the source voltage of the NMOS transistor (12). A PMOS transistor (15) generates a source voltage based on a voltage obtained by adding an absolute value of a threshold voltage and an overdrive voltage to a ground voltage with reference to the ground voltage. A PMOS transistor (19) is turned on/off based on the source voltage of the PMOS transistor (15).